Hello students! Class 8 Science Chapter 2 **Microorganisms: Friend and Foe** mein humne nitrogen fixation aur nitrogen cycle ke baare mein padha hai. Aaj hum padhenge ki kaise tiny bacteria pure atmosphere ki nitrogen cycle ko control karte hain!
Dosto, humare atmosphere mein **78% Nitrogen gas** hai. Lekin plants aur animals ise directly hawa se absorb nahi kar sakte. Ise absorb karne ke liye nitrogen ko soluble nitrates mein convert karna padta hai. Is conversion process ko Nitrogen Fixation kehte hain.
Rhizobium: The Symbiotic Soil Hero
Leguminous plants (jaise chana, matar, pulses) ki roots mein chote-chote bumps hote hain jinhe root nodules kehte hain. In root nodules mein ek special bacterium rehta hai jiska naam hai Rhizobium.
Rhizobium hawa ki nitrogen gas ko soluble nitrates mein convert karke soil mein release karta hai, aur badle mein plant use rehne ke liye shelter aur khana deta hai. Is mutual partnership ko hum biology mein symbiotic relationship kehte hain!
The Continuous Nitrogen Cycle
Soil se plants nitrogen compounds absorb karte hain proteins banane ke liye. Animals in plants ko khate hain. Jab plants aur animals die karte hain, toh decomposers nitrogen compounds ko wapas soil mein release kar dete hain. Aur chote denitrifying bacteria soil se nitrates ko wapas nitrogen gas banakar hawa mein release kar dete hain, jisse atmosphere ka balance bana rehta hai!
⚡ Exam Corner (Biology)
Be ready to outline the five steps of the Nitrogen Cycle in exams: Nitrogen Fixation (Rhizobium/Lightning) -> Nitrogen Assimilation (Plants absorption) -> Ammonification (Decomposition) -> Nitrification (Conversion to Nitrates) -> Denitrification (gaseous release).
Study Taught by Renu Dhaker
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